Method and apparatus for producing multicolored spray dried detergent particles

ABSTRACT

As described herein, hot colorless liquid detergent is continuously supplied under pressure to a plurality of spaced nozzles extending into a spray drying tower. A coloring solution is also supplied under pressure for controlled periods of time to the nozzles wherein the liquid detergent and the coloring solution are thoroughly mixed to form a uniformly colored liquid detergent. The nozzles spray either the colorless liquid detergent or the colored liquid detergent into the interior of the tower wherein the sprayed detergent is dried into either discrete colorless detergent particles or discrete uniformly colored detergent particles.

United States Patent TIMER lnventor Herbert E. Bauer Saddle Brook, NJ.

Appl. No. 782,192

Filed Dec. 9. 1968 Patented July 13, 1971 Assignee Lever Brothers Company New York, N.Y.

METHOD AND APPARATUS FOR PRODUCING MULTICOLORED SPRAY DRIED DETERGENT PARTICLES 8 Claims, 1 Drawing Fig.

U.S. Cl. 159/4, 239/70, 239/305, 252/89, 252/109, 252/134, 252/137, 252/174 Int. Cl 301d 1/16 Field of Search 252/89,

108,109.110, 371, 134,137, 174; l59/4,4B, DIG. 14, 44, 48; 239170, 305, 306

BACK 1 PRESSURE 42/ 6 62 PROPOQTIONIN PUMP iiATIO use [56] References Cited UNITED STATES PATENTS 3,226,030 12/1965 Rossi 239/305 X 3,348,774 10/1967 Wiggins 239/70 3,357,476 12/1967 Tofilemire 159/4 3,450,092 6/1969 Kock 239/70 Primary Examiner-Norman Yudkoff Assistant Examiner--J. Sofer Attorney-Brumhaugh, Graves, Donohue & Raymond ABSTRACT: As described herein, hot colorless liquid detergent is continuously supplied under pressure to a plurality of spaced nozzles extending into a spray drying tower. A coloring solution is also supplied under pressure for controlled periods of time to the nozzles wherein the liquid detergent and the coloring solution are thoroughly mixed to form a uniformly colored liquid detergent. The nozzles spray either the colorless liquid detergent or the colored liquid detergent into the interior of the tower wherein the sprayed detergent is dried into either discrete colorless detergent particles or discrete uniformly colored detergent particles.

BALL-carom VALVES I METHOD AND APPARATUS FOR PRODUCING MULTICOLORED SPRAY DRIED DETERGENT PARTICLES BACKGROUND OF THE INVENTION This invention relates to methods and apparatus for producing multicolored, spray-dried detergent particles.

Generally, in producing colorless or white spray-dried detergent particles, a hot colorless liquid detergent is supplied under pressure to a plurality of spaced nozzles mounted on the wall of a spray drying tower. The nozzles spray the detergent into the tower in droplet form and the droplets are dried into discrete particles by a drying gas generated in the tower.

Recently, there have been marketed multicolored or speckled detergents which combine differently colored detergent particles, such as, for example, blue and white detergent particles. Exemplary of the presently devised systems for spray drying such speckled detergents are the systems described in US. Pat. No. 3,357,476. In one embodiment, one spray nozzle located in the wall of a spray drying tower intermittently receives a colored liquid detergent for injection into the tower. The remaining nozzles continuously inject a colorless detergent into the tower. A disadvantage with this system is that a separate mixer is required to mix the colorless liquid detergent and the coloring solution and that the appearance of the final product is controlled by the number of colorless nozzles being sprayed. In order to achieve a relatively consistent appearance, the number of colorless nozzles in use or amount of colorless liquid being sprayed must be kept constant. This substantially limits the operation and throughput rate of the spray tower. It will further be appreciated that in a commercial installation comprising a multiplicity of nozzles, the cited system will be effective only in producing a product wherein the colored particles are in the minority. In a second embodiment, a coloring solution is intermittently gravity fed to a spray nozzle and mixed with colorless liquid detergent therein for injection into a spray tower. A disadvantage with this system is that the colorless liquid detergent, which is fed to the nozzle under pressure, tends to sweep past the gravity fed coloring solution such that a nonunifon-n and fringe coloring of the liquid detergent results.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method and apparatus for producing multicolored spray-dried detergent particles which overcome the disad-- vantages of the prior art.

This and other objects are accomplished in accordance with the present invention by continuously supplying underpressure a hot liquid detergent to a plurality ofspaced nozzles extending into a spray drying tower. A coloring solution is also supplied under pressure for controlled periods of time to the nozzles and thoroughly mixed therein with the hot liquid detergent to uniformly color the liquid detergent. The nozzles spray the liquid detergent into the interior of the drying tower wherein the spray is subjected to a drying gas and dries into discrete uncolored detergent particles or into discrete colored detergent particles. In a preferred embodiment of the invention, the coloring solution is continuously circulated under pressure in a fixed flow path when not supplied to the nozzles.

BRIEF DESCRIPTION OF THE DRAWING In the Drawing:

The FIGURE is a schematic block diagram of an illustrative system for producing multicolored spray-dried detergent particles arranged according to the present invention.

DESCRIPTION'OF THE PREFERRED EMBODIMENT In the representative system for producing multicolored spray-dried detergent particles arranged according to the invention, as shown in FIG. 1, hot colorless liquid detergent l is stored in a tank or receptacle 12. The hot liquid detergent 10 is extracted from the receptacle 12 by a high pressure pump 14 which supplies the detergent 10 under high "pressure through a conduit 16 to a flow meter 18. The flow meter 18, which may be of conventional construction, measures the quantity of liquid detergent passing through the conduit 16 and provides a visual indication of the quantity in units of rate, such as, for example, gallons per minute. From the flow meter 18, the detergent is fed through a conduit 20 to a ringlike conduit 22 mounted in the wall of a spray drying tower 24. The detergent is then simultaneously supplied to a plurality of valves 26a, 26b-26n situated in parallel with the conduit 22 and in series with a plurality of spray nozzles 28a, 28b-28n, respectively. The nozzles 28a, 28b-28n are mounted in the wall of the tower 24 and include apertured heads which extend into the interior of the spray drying tower 24.

As is understood in the art, the pressure pump 14 supplies thehot liquid detergent to the conduit 22 at sufficiently high pressures to ensure that the nozzles 28a, 28b-28n operate to spray the liquid detergent into the spray drying tower 24 in droplet form. Moreover, in the spray drying tower 24, which may be of conventional construction, the sprayed liquid detergent is subjected to a drying gas which dries the spray into discrete detergent particles, as is understood in the art.

Also provided are a pair of storage tanks 30 and 32 which contain the appropriate coloring solution or dye. As abovementioned, the hot liquid detergent contained'in the receptacle 12 is preferably colorless. When the liquid detergent is colorlessor white, an appropriate coloring solution, such as, for example, a green-dye, is supplied to the tanks 30 and.32. The colorant is supplied simultaneously to the tanks 30 and '32 from a source (not shown) through a conduit 34 and a pair-.of valves 36 and 38 disposed between the conduit 34and the tanks. The colorant is kept in a state of turbulence in both tanks by a pair of agitators and 42 which include'propellors 40a and 42a, disposed adjacent the bottom walls of the tanks 30 and 32, respectively.

The colorant is drawn out from the tanks 30 and 32 through a pair of valves 44 and 45 and supplied under pressure to a conduit 46 by a proportioning pump 48. The pump 48, which may be of the type manufactured by the Milton Roy Company, has an adjustable stroke length or stroking speed such that the quantity of colorant withdrawn from the tanks 30 and 32 can be controlled and, as will be apparent hereinbelow, the colorant concentration in the hot liquid detergent can thereby be controlled.

The colorant forced through the conduit 46 by the-proportioning pump 48 is coupled simultaneously to a relief valve 52 located in a branch conduit 46a of the conduit 46, to a normally open solenoid actuated valve 54 located in a branch conduit 46b, to a valve 55 in series with a surge chamber 56 and to a normally closed solenoid actuated valve 58 included in a branch conduit 460 of the conduit 46. In response to an excessive buildup'ofpressurein the line 46, the relief valve 52 opens to create a flow path between the conduit 46 and the storage tank 30 and thereby relieve the pressure in the conduit.

The operation of the two solenoids associated with the valves 54 and 58 is controlled by a timer 60 which periodically supplies energization current to the solenoids to implement either the opening of the valve 54 and the closing of the valve 58 or the opening of the valve 58 and the closing of the valve 54. As will be more apparent hereinafter, the timer 60 controls the proportionate amount of colored detergent particles spray dried .in the spray drying tower- 24. When it is desired to produce a detergent-having a'grea-ter percentage of colored particles, the timer 60 is set to implement the opening of the valve 58 for a relatively long period of time with valve 54 closed. Conversely, when his desired to have a preponderance of uncolored particles, the timer 60 is set to maintain the valve 54 open and valve 58 closed for relatively long periods of time.

Also included in the branch conduit 46b is a back pressure valve 62 connected in series between the solenoid actuated valve 54 and a pair of valves 64 and 66, respectively, leading to the storage tanks 30 and 32. When the valve 54 opens, the coloring solution is drawn through the conduit 46 and fed under pressure through the valve 54, the back pressure valve 62 and the valves 64 and 66 to the tanks 30 and 32, respectively, such that the colorant is maintained in circulation. It may be noted that the back pressure valve 62 is provided to make certain that a sufficient amount of pressure buildup occurs in the conduit 46 such that the colorant is always present under pressure at the input of the solenoid actuated valve 58 and will quickly pass through the valve 58 when the valve is opened to provide for quick injection of the colorant. An optional surge chamber 56 may be provided for more uniform flow of colorant.

When the valve 58 opens, a flow path is created between the conduit 46 and the branch conduit 46c and the coloring so|ution is fed under pressure to a plurality of valves 62a, 62b-62n situated in series between the branch conduit 46c and the plurality of spray nozzles 28a, 28b-28n mounted within the wall of the spray drying tower 24. A plurality of ball-check valves 64a, 64b-64n are placed in series with and between, valves 62a, 62b-62n and nozzles 28a, 28b-28n. The ball-check valves 64a, 64b64n provide a flow path only for the colorant to the heads of the nozzles. Accordingly, when only the hot liquid detergent is supplied through the valves 26a, 26b-26n to the nozzles or when the detergent is fed to the nozzles under a pressure which exceeds the pressure at which the colorant is supplied, there will not be an undesired flow of the unsprayed colorless or white liquid detergent through the valves 62a, -62" to the branshqqnduit 46 besauscqf th presencgof the ball-check valves 64a, 64b-64n. When the colorant and the liquid detergent meet within the nozzles 28a, 28b28n, the colorant and the liquid detergent mix together with the result that the detergent is uniformly colored by the colorant. The detergent then sprayed into the tower 24 is dried in the tower and colored detergent particles of equal color concentration are produced.

it will be noted that the nozzles 280-2811 spray either colored liquid detergent or uncolored liquid detergent into the spray drying tower 24. Accordingly, there will be developed in the tower 24 a stratified detergent consisting of alternate layers of colored detergent particles and uncolored detergent particles. However, normal swirl patterns within the tower will produce a uniformly speckled or multicolored detergent as discharged from the tower, provided the dye injection cycle time does not exceed the tower residence time of the spraydried particles. Provisions for subsequent blending of the detergent particles in a conventional blender is desirable to as sure uniformity of appearance and to provide additional flexibility in the selection of an injection time cycle.

Coupled to the branch conduit 46c is a return conduit 66 which provides a flow passage for the coloring solution back to the storage tank 30, through a valve 68, during startup periods when valves 62a62n are closed. The ringlike conduit 22 mounted on the tower 24 is also connected to a return conduit 70 which feeds the overflow hot liquid detergent not supplied to the nozzles 28a, 28b-28n back to the storage tank 12 through a flow meter 72 and a valve 74. Opcratively coupled to the flow meter 18 disposed in the liquid detergent supply conduit 16 and the flow meter 72 disposed in the liquid detergent return conduit 70 is a signal subtractor 75. The subtractor signal output which is proportional to the flow of liquid detergent through the nozzles 28a-28n, is in turn operatively coupled to the proportioning pump 48 through a ratio relay 76. The relay 76 which comprises a continuously flow-measur ing and signal-transmitting means and which may be of conventional construction, automatically controls the operation of the proportioning pump 48 on the basis of the volume of liquid detergent being drawn through the conduit 16 and sup plied to the nozzles 28a, 28b-28n. Specifically, once the ratio between the volume of liquid detergent and the volume of colorant to provide colored particles of a desired color concentration is ascertained, the relay may be set to control the output of the pump 48 to insure that the ratio is maintained, notwithstanding fluctuations in the volume of liquid detergent being supplied through the conduit 16.

In operation, hot colorless or white liquid detergent is continuously supplied under pressure by the high pressure pump 14 to the nozzles 28a, 28b-28n which spray the liquid detergent in the form of minute droplets into the interior of the spray drying tower 24. In the tower, the sprayed detergent droplets are acted upon by a drying gas and are dried into dis crete detergent particles. Under control of the timer 60, the coloring solution, which may be, for example, a green dye, is intermittently supplied under pressure from the tanks 30 and 32 and through the conduit 46 and the solenoid actuated valve 58 to the nozzles 280-28". The proportionate amount of colored detergent particles spray dried in the tower 24 may be varied by appropriately varying the setting on the timer 60. Because both the colorant and the liquid detergent are injected into the nozzles 28a, 28b-28n, the colorant and the detergent are thoroughly mixed and the colored detergent particles produced in the tower 24 each have an equal color intensity. This uniform coloring of the detergent is also insured by continuously circulating the colorant between the conduit 46 and the tanks 30 and 32 when the valve 58 is closed and by maintaining a pressure buildup in the conduit 46 during the time that the colorant is circulated to provide quick injection of the colorant when the valve 58 is opened.

Although the invention has been described herein with reference to a specific embodiment many modifications and variations therein will readily occur to those skilled in the art. For example, one three-way solenoid actuated valve may be interposed in the conduit 46 instead of the valves 54.and 58 to create two flow paths for the colorant. Also, each nozzle may have associated therewith a solenoid actuated valve under the control ofa separate timer to implement the continuous spraying of colored detergent particles into the spray drying tower. Accordingly, all such variations and modifications are included within the intended scope of the invention.

lclaim:

1. Apparatus for producing spray-dried multicolored detergent particles comprising: a source of pressurized hot liquid detergent; a source of pressurized coloring solution having an intake means and a discharge means, spray drying tower means including a drying tower having a gaseous drying medium inlet and exhaust gas outlet, a plurality of injector means responsive to liquid under pressure for injecting the liquid detergent as a spray of same into the drying tower and gas flow means to provide a gaseous drying medium within said drying tower for drying the spray into discrete particles; means forming a first open flow path between the source of pressurized hot liquid detergent and the injector means, means forming a normally open shunt flow path for the pressurized color solution between the intake and discharge means of the source of pressurized coloring solution; means forming a normally closed second flow path for the pressurized coloring solution between the discharge means of the source of pressurized coloring solution and the injector means; and timer means including both means for periodically opening the second flow path for the pressurized coloring solution and means for simultaneously closing the shunt flow path for the pressurized coloring solution;

2. Apparatus according to claim 1 wherein the source of pressurized coloring solution comprises receptacle means for containing the coloring solution having inlet and outlet openings and variable pump means coupled to the outlet opening of the receptacle means for drawing out controlled quantities of coloring solution from the receptacle means.

3. Apparatus according to claim 2 further comprising agita- -tor means connected to the receptacle means for maintaining the coloring solution in an agitated state.

4. Apparatus according to claim 2 further comprising back pressure valve means disposed in the normally open shunt flow path for restricting the flow of coloring solution in the 5. Apparatus according to claim 2 further comprising a con-.

tinuous measuring and signal transmission means responsive to the quantity of hot liquid detergent flowing in the first flow path for controlling the operation of the variable pump means.

6. Apparatus according to claim 2 wherein the plurality of injector means comprise a plurality of spray nozzles mounted within the wall of the drying tower and wherein a ball check valve is interposed between each spray nozzle and the normally closed second flow path for the pressurized coloring solution.

7. A method of producing spray-dried multicolored detergent particles comprising the steps of:

a. supplying a hot liquid detergent under pressure in a closed first flow path with an exit branch; b. supplying a coloring solution under pressure in a closed second flow path with an exit branch, said flow paths havmg a common segment; i

c. periodically diverting the coloring solution from the second flow path and supplying the coloring solution under pressure to its flow path exit branch and thence to the hot liquid detergent exit branch;

d mixing together the hot liquid detergent and the coloring solution when the latter is supplied to the first flow path exit branch to uniformly color the hot liquid detergent;

. alternately and sequentially spraying first the hot liquid detergent alone and then the colored hot liquid detergent mixed with hot liquid detergent in droplet form into a defined region; and drying the sprayed droplets respectively into discrete detergent particles and into discrete colored detergent particles in the sequence supplied.

8. A method according to claim 7 comprising the further step of:

a. blending the discrete detergent particles and the discrete colored detergent particles to produce a uniform distribution of the colored detergent particles. 

1. Apparatus for producing spray-dried multicolored detergent particles comprising: a source of pressurized hot liquid detergent; a source of pressurized coloring solution having an intake means and a discharge means, spray drying tower means including a drying tower having a gaseous drying medium inlet and exhaust gas outlet, a plurality of injector means responsive to liquid under pressure for injecting the liquid detergent as a spray of same into the drying tower and gas flow means to provide a gaseous drying medium within said drying tower for drying the spray into discrete particles; means forming a first open flow path between the source of pressurized hot liquid detergent and the injector means, means forming a normally open shunt flow path for the pressurized color solution between the intake and discharge means of the source of pressurized coloring solution; means forming a normally closed second flow path for the pressurized coloring solution between the discharge means of the source of pressurized coloring solution and the injector means; and timer means including both means for periodically opening the second flow path for the pressurized coloring solution and means for simultaneously closing the shunt flow path for the pressurized coloring solution;
 2. Apparatus according to claim 1 wherein the source of pressurized coloring solution comprises receptacle means for containing the coloring solution having inlet and outlet openings and variable pump means coupled to the outlet opening of the receptacle means for drawing out controlled quantities of coloring solution from the receptacle means.
 3. Apparatus according to claim 2 further comprising agitator means connected to the receptacle means for maintaining the coloring solution in an agitated state.
 4. Apparatus according to claim 2 further comprising back pressure valve means disposed in the normally open shunt flow path for restricting the flow of coloring solution in the shunt flow path to maintain an elevated pressure in the normally closed second flow path during the transitional period in which transfer of flow between the shunt flow path and the second flow path occurs, thereby minimizing the time required to pressurize the second flow path and effect flow to the injector means.
 5. Apparatus according to claim 2 further comprising a continuous measuring and signal transmission means responsive to the quantity of hot liquid detergent flowing in the first flow path for controlling the operation of the variable pump means.
 6. Apparatus according to claim 2 wherein the plurality of injector means comprise a plurality of spray nozzles mounted within the wall of the drying tower and wherein a ball check valve is interposed between each spray nozzle and the normally closed second flow path for the pressurized coloring solution.
 7. A method of producing spray-dried multicolored detergent particles comprising the steps of: a. supplying a hot liquid detergent under pressure in a closed first flow path with an exit branch; b. supplying a coloring solution under pressure in a closed second flow path with an exit branch, said flow paths having a common segment; c. periodically diverting the coloring solution from the second flow path and supplying the coloring solution under pressure to its flow path exit branch and thence to the hot liquid detergent exit branch; d. mixing together the hot liquid detergent and the coloring solution when the latter is supplied to the first flow path exit branch to uniformly color the hot liquid detergent; e. alteRnately and sequentially spraying first the hot liquid detergent alone and then the colored hot liquid detergent mixed with hot liquid detergent in droplet form into a defined region; and f. drying the sprayed droplets respectively into discrete detergent particles and into discrete colored detergent particles in the sequence supplied.
 8. A method according to claim 7 comprising the further step of: a. blending the discrete detergent particles and the discrete colored detergent particles to produce a uniform distribution of the colored detergent particles. 